1. Field of the Invention
The present invention relates generally to photolithographic and plasma etch methods for forming patterned metal layers within microelectronics fabrications. More particularly, the present invention relates to wet chemical stripping methods employed within photolithographic and plasma etch methods for forming patterned metal layers within microelectronics fabrications.
2. Description of the Related Art
Microelectronics fabrications are formed from microelectronics substrates upon which are formed patterned microelectronics conductor layers which are separated by microelectronics dielectric layers.
As microelectronics fabrication functionality and integration levels have increased, it has become increasingly more important within the art of microelectronics fabrication to form uniform and reliable patterned microelectronics conductor layers of increasingly narrower linewidth dimensions. While patterned microelectronics conductor layers are thus desirably formed of increasingly narrower linewidth dimensions within advanced microelectronics fabrications to provide advanced microelectronics fabrications of enhanced performance, patterned microelectronics conductor layers with increasingly narrower linewidth dimensions are not formed entirely without problems within advanced microelectronics fabrications.
For example, it is known in the art of advanced microelectronics fabrication that patterned microelectronics conductor layers when formed as patterned microelectronics conductor metal layers through plasma etch methods as are common in the art of advanced microelectronics fabrication often have metal impregnated carbonaceous polymer residue layers formed upon their sidewalls incident to the plasma etch methods. The metal impregnated carbonaceous polymer residue layers typically derive from metal obtained from a blanket microelectronics conductor metal layer from which is formed the patterned microelectronics conductor metal layers through the plasma etch method, along with carbon based polymer materials derived from either: (1) a carbon containing etchant gas composition employed within the plasma etch method; or (2) a slight etching of a series of patterned photoresist layers which is employed in defining the patterned microelectronics conductor metal layers through use of the plasma etch method. Upon stripping from the patterned microelectronics conductor metal layer sidewalls oxygen containing photoresist stripping plasma oxidized metal impregnated polymer residue layers formed from the metal impregnated carbonaceous polymer residue layers while employing an aqueous alkyl ammonium hydroxide based photoresist developer solution such as but not limited to an aqueous tetramethyl ammonium hydroxide (TMAH) based photoresist developer solution or an aqueous trimethyl (2-hydroxyethyl) ammonium hydroxide (ie: choline) based photoresist developer solution there is often corroded or eroded at least the sidewalls of the patterned microelectronics conductor metal layer. A series of schematic cross-sectional diagrams illustrating the results of forming within a microelectronics fabrication a pair of such corroded or eroded patterned microelectronics conductor metal layers is shown in FIG. 1 to FIG. 3.
Shown in FIG. 1 is a substrate 10 employed within a microelectronics fabrication, where the substrate 10 has a blanket conductor metal layer 12 formed thereover. In turn, the blanket conductor metal layer 12 has formed thereupon a pair of patterned photoresist layers 14a and 14b. As is illustrated in FIG. 2, when the blanket conductor metal layer 12 is etched to form a pair of patterned conductor metal layers 12a and 12b through use of a metal etching plasma 16 while simultaneously employing the pair of patterned photoresist layers 14a and 14b as a photoresist etch mask layer, there is formed upon the sidewalls of the patterned conductor metal layers 12a and 12b a series of metal impregnated carbonaceous polymer residue layers 18a, 18b, 18c and 18d.
As shown in FIG. 3, upon stripping from the microelectronics fabrication whose schematic cross-sectional diagram is illustrated in FIG. 2: (1) the patterned photoresist layers 14a and 14b (through use of an oxygen containing plasma stripping method sequential and subsequent to a metal etching plasma method employing the metal etching plasma 16); and (2) a series of oxygen containing stripping plasma oxidized metal impregnated polymer residue layers formed from the series of metal impregnated carbonaceous polymer residue layers 18a, 18b, 18c and 18d (through use of an aqueous alkyl ammonium hydroxide based photoresist developer solution such as but not limited to an aqueous tetramethyl ammonium hydroxide (TMAH) based photoresist developer solution or an aqueous choline based photoresist developer solution), there is typically formed a pair of etched patterned conductor metal layers 12a' and 12b', which as illustrated in FIG. 3 are either corroded or eroded, from the patterned conductor metal layers 12a and 12b as illustrated in FIG. 2.
Etched patterned metal layers, such as the etched patterned conductor metal layers 12a' and 12b' as illustrated in FIG. 3, are undesirable within the art of microelectronics fabrication since it is often difficult to form fully functional or reliable microelectronics circuits within microelectronics fabrications having formed therein such etched patterned metal layers.
It is thus towards the goal of forming within microelectronics fabrications patterned conductor metal layers through plasma etch methods and subsequently stripping from the sidewalls of the patterned conductor metal layers so formed oxidized metal impregnated polymer residue layers formed incident to the plasma etch methods, the oxidized metal impregnated polymer residue layers being stripped while employing aqueous alkyl ammonium hydroxide based solutions such as but not limited to aqueous tetramethyl ammonium hydroxide (TMAH) based photoresist developer solutions and aqueous choline based photoresist developer solutions, with attenuated corrosion or erosion of the patterned conductor metal layers, that the present invention is directed. Within the present invention corrosion and erosion of patterned metal layers are intended as analogous, and possibly related, physical deterioration phenomena experienced by patterned metal layers.
Various methods have been disclosed in the pertinent arts for attenuating corrosion and related metal layer deterioration phenomena encountered within metal layers, in particular aluminum containing metal layers, at least some of which may be formed within microelectronics fabrications.
For example, Landau et al., in U.S. Pat. No. 4,592,800, discloses a method for inhibiting corrosion of a patterned aluminum containing conductor metal layer formed through a plasma etch method within an integrated circuit microelectronics fabrication. The method employs displacing volatile corrosive species sorbed on or near the patterned aluminum containing conductor layer within the microelectronics fabrication incident to the plasma etch method with more readily sorbed non-corrosive volatile species of higher molecular weight.
In addition, Murakami et al., in U.S. Pat. No. 5,312,776 similarly also discloses a method for inhibiting corrosion of a patterned conductor metal layer, which may be a patterned aluminum containing conductor metal layer, formed through a plasma etch method within an integrated circuit microelectronics fabrication. The method employs forming a hydrophobic molecular layer, while employing a material such as hexamethyldisilazane (HMDS), upon at least the exposed lateral surfaces of the patterned conductor metal layer.
Further, Nadkarni, in U.S. Pat. No. 5,514,478, discloses a non-abrasive and corrosion resistant hydrophilic coating for an aluminum substrate, along with its method of application upon the aluminum substrate. The coating contains effective minor amounts of nitrilotrismethylenetriphosphonic acid, phosphoric acid, a borate material and a polyacrylic acid, without silica or alumina type materials, which when thermally cured upon an aluminum substrate provides a hydrophilic coating exhibiting a stable water contact angle of no greater than about 15 degrees.
Yet further, Obeng in U.S. Pat. No. 5,538,921, also discloses a method for attenuating corrosion of a patterned conductor metal layer, such as a patterned aluminum containing conductor metal layer, formed through a plasma etch method within an integrated circuit microelectronics fabrication. The method employs rinsing the integrated circuit having the patterned conductor metal layer formed therein with an aqueous solution of a non-ionic or an ampholytic surfactant.
Finally, Yano et al., in U.S. Pat. No. 5,569,628, discloses several methods for attenuating corrosion related problems, such as interdiffusion, when forming patterned metal layers, such as patterned aluminum containing conductor layers, upon substrates within integrated circuit microelectronics fabrications. The methods employ forming a molecular film of a silicon material upon a substrate layer employed within an integrated circuit microelectronics fabrication, where a metal layer when subsequently formed upon the molecular film reacts with the molecular film and forms a metal layer deposited upon only the molecular layer and not interdiffused with the substrate layer.
Desirable within the art of microelectronics fabrication are methods through which there may be stripped from the sidewalls of patterned conductor metal layers formed employing plasma etch methods within microelectronics fabrications oxidized metal impregnated polymer residue layers formed incident to the plasma etch methods, the oxidized metal impregnated polymer residue layers being stripped through use of aqueous alkyl ammonium hydroxide based solutions such as but not limited to aqueous tetramethyl ammonium hydroxide (TMAH) based photoresist developer solutions and aqueous choline based photoresist developer solutions, with attenuated corrosion or erosion of the patterned conductor metal layers. It is towards that goal that the present invention is directed.